Two scientific studies into the impact of the Montara oil spill have been released and have found no oil reached Australia's mainland or the Indonesia coast.
Two scientific studies into the impact of the Montara oil spill have been released and have found no oil reached Australia's mainland or the Indonesia coast.
The spill started in the Timor Sea on August 21 last year and latest for two months.
The Federal Government continues to sit on a report into the country's worst oil spill.
Energy Minister Martin Ferguson has said the report contains 105 recommendations and has said on a number of occasions that it will be released before Christmas.
The scientific studies completed by PTTEP Australasia and the Department of Sustainability, Environment, Water, Population and Communities covered an analysis of the movement and distribution of oil from the spill; and the fate and effects of the use of dispersants to mitigate the spill.
The first study released by the Department was undertaken by Asia-Pacific ASA and documented all oil spill positions from field and overflight data, satellite observations and integrated hindcast oil spill trajectory modeling.
"The combination of these various datasets highlighted that the highest occurrence of oil was within a distance of 22.8km (12.3 NM) of the release site and was mostly comprised of think and relatively fresh oil," the report said.
"Beyond this zone surrounding the immediate spill area, oil occurrences were generally patchy and more highly weathered (often changing colour).
"Indeed, images of the slick at extents beyond 22.8 km were predominantly sheens/waxy films even waxy solids and surface coverage was significantly less which is typical of oil spill dynamics at these distances from the source," the report stated.
The report found that the area swept by 99 per cent of the oil was limited to a radial distance of 82 kilometres.
Ninety-eight-point-six per cent of the swept area remained in Australian Territorial Waters.
The second study on the effects of dispersants to mitigate the effects of the spill found the maximum concentration of hydrocarbond in the water colum at any depth following the release of the dispersant was 3.48 parts per million.
"The modeling indicated that the effect of the addition of the chemical dispersant to the oil spill of the Montara WHP caused an elevation of hydrocarbon concentrations in the water column that was extremely localised and of short duration," the study said.
PPTEP Australasia welcomed the release of the reports.
"The company committed early on to funding the scientific studies. Commitments to run some of the studies beyond two years does not necessarily indicate long-term impacts but supports the recommendations of independent experts to ensure the best science is in place to monitor the marine environment," a PTTEPAA spokesman said.
"The studies are creating a body of high quality scientific baseline data in key areas of the Timor Sea marine environment. This will be an asset for the industry and the community in managing activities in the region."
In August, the Environmental Protection Authority released a study which found the Kimberley coast line escaped contamination from the spill.
The spill prompted the EPA to investigate and testing was conducted on water, sand and pearl oysters in October and December last year.
The samples were taken from islands, four pearl farms and peninsulas from Camden Sound in the south to the Stewart Islands in the northeast.
The EPA report found no petroleum hydrocarbons in any of the water or shoreline sediment samples at concentrations above the analytical limits of detection.
See statement from PTTEP Australasia below:
PTTEP Australasia (PTTEPAA) welcomes the public release of the first independent scientific studies conducted under the long-term environmental monitoring program developed by the company and the Australian Government during the Montara incident last year.
The two studies released today by the Department of Sustainability, Environment, Water, Population and Communities (SEWPAC) cover an analysis of the movement and distribution of oil from the spill in the Timor Sea; and the fate and effects of the use of dispersants to mitigate the effects of the spill.
Key findings of the studies included:
- No oil reached the Australian mainland or Indonesian coast.
- The maximum surface area of the ocean that had hydrocarbons on it on any one given day was 11,183 square kilometres.
PTTEPAA has worked closely with the Federal Government to develop the environmental monitoring program, including appointing independent leading marine science experts from a range of research organisations to undertake 11 of 12 possible studies which have been triggered to date.
Independent expert advice was sought by the Federal Government on the detail of the monitoring plan announced in October 2009 from organisations such as the Australian Institute of Marine Science (AIMS), CSIRO and State and Territory agencies.
Each study conducted under the PTTEPAA/SEWPAC monitoring program is subject to a detailed review by SEWPAC's technical advisory board. A summary of the three studies is provided below:
S7.1 Oil Fate and Effects Assessment - Trajectory Analysis
The S7.1 and 7.2 studies were undertaken by Asia-Pacific ASA, an Australian company which specialises in the development and application of sophisticated tools for application to environmental issues with a focus on physical, chemical and biological processes in marine and aquatic environments (www.apasa.com.au). The studies were headed by senior oceanographer Dr Brian King and senior chemist and environmental scientist Trevor Gilbert.
They provided the most comprehensive (hourly) understanding of the spill, combining trajectory modeling, overflight data and satellite images. The S7.1 study reported, in part:
- That no oil reached the Australian mainland or Indonesian coast.
- The maximum surface area of the ocean that had hydrocarbons on it on any one given day was 11,183 square kilometers.
- The greatest occurrence of oil was within 22.8 kilometres of the release site.
- Beyond 22.8 kilometres, the hydrocarbons were predominantly sheens/waxy films and of short duration.
- 98.6% of occurrences of hydrocarbons on surface were within Australian water.
S7.2 Oil Fate and Effects Assessment - Dispersant Oil Modeling
The S7.2 study reported, in part:
- The chemical dispersant application caused elevations in hydrocarbon concentrations in the water column, mostly within the first metre of the water column however these concentrations reduced quickly with time, depth and distance from the dispersant application site and no dispersed oil reached the Australian mainland or Indonesian coast.
PTTEPAA is funding the comprehensive monitoring program for at least two years, although some studies will continue for up to five years, or even longer if required to provide data to measure and appropriately address any longer term impacts should they occur - now and in the future.
"The company committed early on to funding the scientific studies. Commitments to run some of the studies beyond two years does not necessarily indicate long-term impacts but supports the recommendations of independent experts to ensure the best science is in place to monitor the marine environment," a PTTEPAA spokesman said.
"The studies are creating a body of high quality scientific baseline data in key areas of the Timor Sea marine environment. This will be an asset for the industry and the community in managing activities in the region."
PTTEPAA looks forward to further scientific studies being released.
